Rotary loop-takers for sewing machines



March 27, 1956 RWBREUL I 2,739,554

ROTARY LOOP-TAKERS FOR SEWING MACHINES Filed Sept. 3, 1953 a I l 10 2 i '5? Fig.2 MN 8 I 7 Fig. 3.

' INVENTOR.

Fredric W. Breul WITNESS ATTORNEY Unite States Patent RGTARY LOOP-TAKERS FOR SEWING MACHINES Fredric W. Breul, Bridgeport, Conn., assignor to The Singer Manufacturing Company, Elizabeth, N. J., a corporation of New Jersey Application September 3, 1953, Serial No. 378,202

1 Claim. (Cl. 112-228) The present invention relates to rotary loop-takers for sewing machines and has for a primary object to improve upon rotary loop-takers as heretofore constructed. More specifically, it is an object of the present invention to provide means for remedying the condition which results in damage to the leading end of the bobbin-carrier raceway in the body portion of a rotary loop-taker.

Having in mind the above and other objects that will be evident from an understanding of this disclosure, the invention comprises the devices, combinations and arrangements of parts as illustrated in the presently preferred embodiment of the invention which is hereinafter set forth in such detail as to enable those skilled in the art readily to understand the function, operation, construction and advantages of it when read in conjunction with the accompanying drawings in which:

Fig. 1 is a top plan view of a rotary hook for a sewing machine, which rotary hook embodies the present invention.

Fig. 2 is a section view of the hook-body per so taken substantially on the line 2-2 of Fig. 1 with the bobbincarrier removed.

Fig. 3 is a fragmentary section view taken substantially on the line 33 of Fig. l but with the hook-body slightly rotated with respect to the bobbin-carrier wherein the bearing-rib on the bobbin-carrier has entered the raceway of the hook-body.

The loop-taker that has been selected to illustrate the present invention is a vertical-axis rotary hook that includes a hook-shaft 1 surmounted by an integral hubportion 2 of a cup-shaped hook-body 3. The cylindrical side-wall and bottom-wall of the hook-body 3 are cutaway in the usual manner along the line 4 (Fig. 1) to provide a gap into which the integral hook-beak 5 extends, and the bottom-wall but not the side-wall is cutaway along the line 6 to properly balance the rotary hook dynamically. In the customary manner, the side-wall of the hook-body is provided with a circular bobbin-carrier raceway 7 comprising a bottom-wall 8 and upper and lower side-walls 9, which raceway is formed entirely within the side-wall of the hook-body in the area adjacent the beak 5, but is formed with the upper side thereof open in the remaining portion of the side-wall of the hookbody, the open-sided portion thereof being closed by a gib 10 secured to the hook-body by screws 11. The raceway 7 thus provided in the hook-body 3 is continuous except for the gap formed by the cut-away portion defined by the line 4.

Iournaled in the raceway 7 is the peripheral bearing rib 12 of a bobbin-carrier 13 which may be of any suitable construction. In the usual manner, the bearing rib 12 is discontinuous to provide a thread-clearance gap between the opposed ends 14 and 15 (Fig. 1) of the bearing rib 12; the end 14, which is the needle-thread loop-detaining shoulder being designated the leading end. The above construction is all old and well known and it is not deemed necessary to further expand this disclosure in relation thereto. The details of the mechanism disclosed and the method of operation in stitch formation will be obvious to those skilled in the art.

During operation of the disclosed hook, the body 3 rotates in the direction of the arrow A, Fig. 1, with respect to the relatively stationary bobbin-carrier 13. That end of the raceway 7 adjacent the beak 5 is defined as a leading end 16. It is this end 16 that initially receives the leading end 14 of the bearing rib 12 upon relative movement between the hook-body and the bobbin-carrier. Heretofore, it has been the practice to form the raceway 7 of uniform rectangular cross-section throughout its length. Thus, the raceway 7 at the leading end 16 would initially receive the leading end 14 of the bearing rib 12 with very small clearance as the gaps or discontinuous portions of the raceway 7 and the bearing rib 12 would pass. Because of looseness due to manufacturing tolerances or wear, there is a tendency for the side-walls of the leading ends of the bearing rib 12 and the raceway 7 to collide and the side-Walls 9 of the raceway 7 at the leading end 16 are thus broken away. When so broken away, the resulting roughness will cut the needlethread and thus necessitate replacement or repair of the hook.

In accordance with the objects of the present invention, means have been provided for conducting the thread-loop detaining shoulder 14 into the raceway 7 more smoothly and thereby preventing collision thereof with the side-walls 9 of the raceway and consequent destruction of the same. As will be seen with reference to the drawings, adjacent the leading end 16 of the raceway 7, the side-walls 9 thereof are flared or beveled outwardly from the bottom-wall 8 and toward the leading end 16 of the raceway 7, as at 17. From the above, it will be seen that as the raceway 7 rotates relative to the bobbin-carrier 13, and as it passes the discontinuous portion of the bearing-rib 12, it will be smoothly guided back onto the bearing rib over the leading end 14 by the flared portions 17 of the side-walls 9.

Numerous alterations of the structure herein disclosed will suggest themselves to those skilled in the art. However, it is to be understood that the present disclosure relates to a preferred embodiment of my invention which is for purposes of illustration only and not to be construed as a limitation of the invention. All such modifications which do not depart from the spirit of the invention are intended to be included within the scope of the appended claim.

Having thus described my invention, what I claim herein is:

In a rotary hook for a sewing machine including a cup-shaped body-portion having a loop-seizing beak and an internal circular raceway having a gap therein adjacent said loop-seizing beak, said raceway comprising a closed portion having one end adjacent said loop-seizing beak provided with a bottom-wall and opposed side-walls and an open-sided portion, a gib for closing the opensided portion of said raceway, and a thread-carrier having a peripheral bearing rib complemental to and adapted to be seated in said raceway, said bearing rib having a gap therein to provide a thread loop-detaining shoulder, said body-portion being adapted to be rotated during stitch-formation and said thread-carrier being adapted to ayraaesa remain substantially stationary during rotation of said body-portion whereby said raceway will be rotated relative to said bearing rib, said raceway having a leading end comprising the end of said closed portion adjacent said gap, and said side-walls of the closed portion of said raceway at the leading end thereof being flared outwardly from said bottom-wall and toward said leading end whereby side-walls are divergent from said bottom-wall outwardly and toward said leading end, said side-walls being flared to prevent collision between the side-walls 10 2,435,358

References Cited in the file of this patent UNITED STATES PATENTS Colegrove Oct. 26, 1943 Kessler Feb. 3, 1948 

